On-line information retrieval systems are utilized for searching and retrieving many kinds of information. Most systems used today work in essentially the same manner; that is, users log on (through a computer terminal or personal microcomputer, and typically from a remote location), select a source of information (i.e., a particular database) which is usually something less than the complete domain, formulate a query, launch the search, and then review the search results displayed on the terminal or microcomputer, typically with documents (or summaries of documents) displayed in reverse chronological order. This process must be repeated each time another source (database) or group of sources is selected (which is frequently necessary in order to insure all relevant documents have been found). Additionally, this process places on the user the burden of organizing and assimilating the multiple results generated from the launch of the same query in each of the multiple sources (databases) that the user needs (or wants) to search. Present systems that allow searching of large domains require persons seeking information in these domains to attempt to modify their queries to reduce the search results to a size that the user can assimilate by browsing through them (thus, potentially eliminating relevant results).
In many cases end users have been forced to use an intermediary (i.e., a professional searcher) because the current collections of sources are both complex and extensive, and effective search strategies often vary significantly from one source to another. Even with such guidance, potential relevant answers are missed because all potentially relevant databases or information sources are not searched on every query. Much effort has been expended on refining and improving source selection by grouping sources or database files together. Significant effort has also been expended on query formulation through the use of knowledge bases and natural language processing. However, as the groupings of sources become larger, and the responses to more comprehensive search queries become more complete, the person seeking information is often faced with the daunting task of sifting through large unorganized answer sets in an attempt to find the most relevant documents or information.